• Journal of Astronomy and Space Sciences
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• v.35 no.2
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• pp.105-109
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• 2018

El $Ni{\tilde{n}}o$ is the largest fluctuation in the climate system, and it can lead to effects influencing humans all over the world. An El $Ni{\tilde{n}}o$ occurs when sea surface temperatures in the central and eastern tropical Pacific Ocean become substantially higher than average. We investigated the change in sea surface temperature in the Pacific Ocean during the El $Ni{\tilde{n}}o$ period of 2015 and 2016 using the advanced very-high-resolution radiometer (AVHRR) of NOAA Satellites. We calculated anomalies of the Pacific equatorial sea surface temperature for the normal period of 1981-2010 to identify the variation of the 2015 El $Ni{\tilde{n}}o$ and warm water area. Generally, the warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America during an El $Ni{\tilde{n}}o$ period. However, we identified an additional warm water region in the $Ni{\tilde{n}}o$ 1+2 and Peru coastal area. This indicates that there are other factors that increase the sea surface temperature. In the future, we will study the heat coming from the bottom of the sea to understand the origin of the heat transport of the Pacific Ocean.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.786-789
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• 2003

The detection of sandstorms and industrial pollutants has been the emphasis of this study. Data obtained from meteorological satellites, NOAA and GMS, have been used for detailed analysis. MODIS and Landsat images are also used for the application of future KOMPSAT- 2. Verification of satellite observations has been made with air pollution data obtained by ground-level monitors. It was found that satellite measurements agree well with concentrations and variations of air pollutants measured on the ground, and that satellite technique is a very useful device for monitoring large-scale air pollution in East Asia. The quantitative analysis of satellite image data on air pollution is the goal in the future studies.

• Ocean and Polar Research
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• v.23 no.1
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• pp.1-10
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• 2001

Sea surface temperature derived from infrared images of NOAA satellites showed a warm eddy in the East Korean Bight(EKB) or Donghan Man during the winter 1997${\sim}$2000. To describe the warm eddy in the EKB, hydrographic data collected in 1934 and 1936 were also analyzed. The center of the warm eddy was located at about $39^{\circ}N$ and $129^{\circ}E$. The temperature and salinity of the eddy was about $4.0^{\circ}C$ and 34.0 psu, respectively, at 100m depth. The eddy rotated anticyclonically with a geostrophic current speed of about 20 cm/s. The mean state calculated from the data of 1922${\sim}$1960 showed the existence of a warm eddy over the EKB in winter. The eddy persists until late spring, and disappears from the previous location in summertime, only to be seen again in autumn.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.166-178
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• 2015

We investigated marine environmental characteristics of Goheung coastal areas in August where is known to be the first outbreak site of Cochlodinium polykrikoides (hereafter C. polykrikoides) blooms, based on the oceanographic data observed from 1993 to 2013 around the Korean southern coastal waters including Eastern China Sea by National Fisheries Research and Development Institute (NFRDI). The data of NOAA/NGSST satellite images as well as numerical simulation results by Seo et al. [2013] were also used for analysis. Water temperatures at the surface and bottom layers in Goheung coast, i.e. Narodo, were $25.0^{\circ}C$ and $23.7^{\circ}C$ so that they were higher than $23.8^{\circ}C$ and $19.4^{\circ}C$ in Geoje coast where is a reference site, respectively. In addition, salinities at the surface and bottom layers in Goheung coast were 31.78 psu and 31.98 psu so that they were a little higher than 31.54 psu at the surface but a little lower than 32.79 psu at the bottom in Geoje coast, respectively. That is, the differences in water temperature or salinity between the surface and bottom layers in Goheung coast in August were not large compared to Geoje coast. This suggests that stratification in Goheung coast in August is fairly weak or may not be established. In addition, the concentrations of DIN and DIP at the surface layer were 0.068 mg/L ($4.86{\mu}M$) and 0.015 mg/L ($5.14{\mu}M$) in Goheung coast while 0.072 mg/L ($5.14{\mu}M$) and 0.01 mg/L ($0.32{\mu}M$) in Geoje coast, so they did not indicate a meaningful difference. On the other hand, when C. polykrikoides blooms, water temperature and salinity in August at the station 317-22 ($31.5^{\circ}N$, $124^{\circ}E$) of the East China Sea, where is near the mouth of Yangtze River, were $27.8^{\circ}C$ and 31.61 psu, respectively. Thus, water temperature was much higher whereas salinity was almost similar compared to Goheung coast. Furthermore, concentrations of $NO_3-N$ and $PO_4-P$ in the East China Sea in August were remarkably high compared to Goheung coast. When C. polykrikoides blooms, according to not only the image data of satellites NOAA/NGSST but also numerical experiment results by Seo et al.[2013], the freshwater out of Yangtze River was judged to clearly affect the Korean southern coastal waters. Therefore, the supply of nutrients in terms of Yangtze River may greatly contribute to the outbreak of C. polykrikoides blooms in Goheung coast in summer.

• Journal of Astronomy and Space Sciences
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• v.11 no.1
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• pp.71-80
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• 1994

It is generally known that the measurement of the ionospheric total electron content(TEC) by GPS can more accurately monitor the broader area of the ionosphere than other current methods. \Ve measured the TEC along a slant path considering the arrival time differences of P-code which is transmitted from GPS satellites with the modulation on two L-band carrier frequencies, L1 (1574.42MHz) and L2 (1227.60MHz). Under the assumptions that the ionosphere is uniformly distributed and its average height is 350km, we transformed the slant TEC to the vertical TEC at the point that the line-of-sight direction to GPS satellite cut across the average height of the ionosphere. Because there is no dual frequency P-code GPS receiver in Korea, we used the data observed at the TAIW GPS station ($N25^{\circ},E121.5^{\circ}$) in Taiwan which is one of the core stations in International GPS and Geodynamics Services (IGS). The TEC values obtained in this work showed a typical daily variation of the ionosphere which is high in the daytime and low in the nighttime. Our results are found to be consistent with the SOLAR-DAILY data of NOAA and the Klobuchar's model for the ionospheric correction of GPS. In addition, in the cornparision with SOLAR-DAILY data, we estimated the precision of our TEC measurement as 2 TEC.

• Journal of the Korean earth science society
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• v.21 no.5
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• pp.503-524
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• 2000

Intercomparisons between four kinds of data have been done to estimate the accuracy of satellite observations and model reanalysis for middle and lower tropospheric thermal state over regional oceans. The data include the Microwave Sounding Units (MSU) Channel 2 (Ch2) brightness temperatures of NOAA satellites and the vertically weighted corresponding temperature of ECMWF GCM (1980-93). The satellite data for midtropospheric temperatures are MSU2 (1980-98) in nadir direction and SC2 (1980-97) in multiple scans, and for lower tropospheric temperature SC2R (1980-97). MSU2 was derived in this study while SC2 and SC2R were described in Spencer and Christy (1992a, 1992b). Temporal correlations between the above data were high (r${\ge}$0.90) in the middle and high latitudes, but low(r${\sim}$0.65) over the low latitude and more convective regions. Their values with SC2R which included the noises due to hydrometeors and surface emission were conspicuously low. The reanalysis shows higher correlation with SC2 than with MSU2 partially because of the hydrometeors screening. SC2R in monthly climatological anomalies was more sensitive to surface thermal condition in northern hemisphere than MSU2 or SC2. The first EOF mode for the monthly mean data of MSU and ECMWF shows annual cycle over most regions except the tropics. The mode in MSU2 over the Pacific suggests the east-west dipole due to the Walker circulation, but this tendency is not clear in other data. In the first and second modes for the Ch2 anomalies over most regions, the MSU and ECMWF data commonly indicate interannual variability due to El Ni${\tilde{n}$o and La Ni${\tilde{n}$a. The substantial disagreement between observations and model reanalysis occurs over the equatorial upwelling region of the western Pacific, suggesting uncertainties in the model parameterization of atmosphere-ocean interaction.